10 meter mobile antenna
 

OK where can I buy a 330pf cap? Its only a 25 watt rig but I would like a
bit of overkill.
****es me off that Radio Shack is a cell phone store now. I used to be able
to walk into Radio Shack and the person there would understand what you
needed. Now if it does not have to do with cell phones or car audio they
just give you this dumb look..

Thanks
Joe

vertical without having to cut it.

I did exactly this (20 years ago). I used a variable compression trimmer
capacitor to check that I could actually get a low SWR, measured it, and
fitted the nearest value disc ceramic (rated at 500VDC). I think it was
330pF. No problems with 40W.
Ian.
--

10 meter mobile antenna
 

Merlin-7 KI4ILB wrote:
OK where can I buy a 330pf cap?

Make it a silver mica or doorknob. I get mine at an
electronics supply store in Bryan, TX, close to
Texas A&M. Where are you located?
--
73, Cecil, http://www.qsl.net/w5dxp

10 meter mobile antenna
 

"Now if it does not have to do with cell phones or car audio they
just give you this dumb look.. "

Heh.. went into my local Radio Shack and asked if they had any antenna
masts in stock. Guy goes and looks on the shelves. I say "I'd like a
TV mast, it's in the back if you have it, it's ten feet long" Guy
looks on the shelves some more, points to the mast brackets.

I'm like, "It's a ten feet long piece of steel pipe it wouldn't be out
here, it isn't out here, it wouldn't fit out here, it's in the BACK."
I look it up on the internet on the computer in the store and show them
that yes, they do have them in stock.

Of course, he doesn't think they've got any. Twenty minutes after I
walk in, I'm finally leaving with a five foot and a ten foot mast
section which they, of course, had. Guy is just incredulous that I'm
going to walk out of the store with a ten foot piece of pipe. They
then ask me if I need a cell phone ;-)

Dan

10 meter mobile antenna
 

"Merlin-7 KI4ILB" wrote in message
. ..
I just bought a 10 meter mobile rig (25 watt old radio shack rig).

I was planing on cutting down a 102" CB whip to 10 meter band.

Anyone know of any type of antenna that would work better?

Thanks
Joe
KI4ILB



A 1/8wl antenna mounted in the center of your roof will probably work better
than the 1/4 lambda antenna on the bumper.

10 meter mobile antenna
 

On Thu, 26 Oct 2006 22:53:48 GMT, "Merlin-7 KI4ILB"
wrote:

OK where can I buy a 330pf cap? Its only a 25 watt rig but I would like a
bit of overkill.
****es me off that Radio Shack is a cell phone store now. I used to be able
to walk into Radio Shack and the person there would understand what you
needed. Now if it does not have to do with cell phones or car audio they
just give you this dumb look..

Thanks
Joe

I've been able to mail order most any electrical part from Mouser. No
minimum order. And it puts you on the list for their huge catalog.

bob
k5qwg



vertical without having to cut it.

I did exactly this (20 years ago). I used a variable compression trimmer
capacitor to check that I could actually get a low SWR, measured it, and
fitted the nearest value disc ceramic (rated at 500VDC). I think it was
330pF. No problems with 40W.
Ian.
--

10 meter mobile antenna
 

It would not be mounted on the bumper.
My thinking is that since the first 1/3 of an antenna does the most
radiating, get it as far away from any metal (broadside) that you can.
It would be mounted in a stake-hole (one of the 4 square holes in each
corner of the truck bed.
Joe

A 1/8wl antenna mounted in the center of your roof will probably work
better
than the 1/4 lambda antenna on the bumper.

10 meter mobile antenna
 

Ok which one would you recommend?

http://www.mouser.com/search/Refine.... f&N=1323038+0

Thanks
joe



I've been able to mail order most any electrical part from Mouser. No
minimum order. And it puts you on the list for their huge catalog.

bob
k5qwg



vertical without having to cut it.

I did exactly this (20 years ago). I used a variable compression
trimmer
capacitor to check that I could actually get a low SWR, measured it,
and
fitted the nearest value disc ceramic (rated at 500VDC). I think it was
330pF. No problems with 40W.
Ian.
--

10 meter mobile antenna
 

"Merlin-7 KI4ILB" wrote in message
. ..
Ok which one would you recommend?

http://www.mouser.com/search/Refine.... f&N=1323038+0

Thanks
joe



I've been able to mail order most any electrical part from Mouser. No
minimum order. And it puts you on the list for their huge catalog.

bob
k5qwg



vertical without having to cut it.

I did exactly this (20 years ago). I used a variable compression
trimmer
capacitor to check that I could actually get a low SWR, measured it,
and
fitted the nearest value disc ceramic (rated at 500VDC). I think it
was
330pF. No problems with 40W.
Ian.


I once saw a 102" whip on a motor home that had literally been wound into a
4 " dia coil about half way up! It looked like one of those CB "big coil"
trucker antennas except it was all in one piece. I can only surmise that he
heated it and wound it around some sort of form. It shortened the thing down
to less that 5 feet. But, then, wouldn't that take the temper out of the
steel and make it flop over the next time it was hit? There was also no
evidence of heating, either; it looked like it had been formed at the
beginning of its life. Anybody ever see anyone do this before. If so, how
was it done?

73

Jerry
--

10 meter mobile antenna
 

"Merlin-7 KI4ILB" wrote in message
.. .
It would not be mounted on the bumper.
My thinking is that since the first 1/3 of an antenna does the most
radiating, get it as far away from any metal (broadside) that you can.
It would be mounted in a stake-hole (one of the 4 square holes in each
corner of the truck bed.
Joe

A 1/8wl antenna mounted in the center of your roof will probably work
better
than the 1/4 lambda antenna on the bumper.


To each his own, but I don't agree with the "bottom" of the antenna doing
the radiating. :) The bottom, *if* I understand it correctly--and I am not
here to prove anything or start a flame war (I ain't got time for that
;) )--is the voltage portion, the top would be the current (RF) portion.
Witness what happens if you grab an antenna (dipole. The current at the
ends can reach levels to produce serious burns! Grab a mobile antenna below
the loading coil while transmitting. You won't feel a thing! Grab it at or
above the coil, it will burn the hell out of you ( X-numbers of milliamps of
RF current). The next thing is, IMHO, if your antenna is radiating from the
bottom, WHY would you even NEED the rest of the antenna? LOL! Next there's
those pesky ground proximities that tend to "grab" a signal and just spoil
everything.

Now I am not trying to start a war, prove anyone wrong, annoy anyone, or
engage in a "I'm-smarter-than-you-and-I'm-not-gonna-yield" etc, etc. I'll
yield because it is 1) not important to me) and 2) cuz I ain't got time to
get into a theory war today! ;) But, I am just of the opinion that the RF
is where the thing will burn the crap out of you if you grab it!!! I've been
burnt plenty of times, and it ain't pleasant!!!

73

Jerry

10 meter mobile antenna
 

Jerry wrote:
The bottom, *if* I understand it correctly--is the voltage portion,
the top would be the current (RF) portion.

Nope, for a 1/4WL mobile antenna, the feedpoint is the
high current, low voltage point. The tip top is the
low current, high voltage point. The thing that tends
to bite us is the high voltage.

Consider that the top portion of a mobile antenna can
be a low-radiation top hat while the bottom of the
antenna (high current section) is radiating very well.
--
73, Cecil http://www.w5dxp.com